Heatable vehicle windows are known in the art, and typically include first and second conductive bus bars in electrical contact with a conductive coating including at least one electro conductive layer. The electro conductive layer(s) generates heat when electric current is passed therethrough via the bus bars. In such a manner, snow and ice may be melted from vehicle windows such as windshields, backlites, and/or the like. Windows may also be defogged in such a manner. Example heatable vehicle windows are described and illustrated in U.S. Pat. Nos. 6,906,287, 6,559,419, 6,870,134, and 6,625,875, the disclosures of which are all hereby incorporated herein by reference.
The bus bars are utilized to cause electric current to pass through the heatable layer(s) of the coating. This means that electrical connections must be made between the bus bars and external connectors. Solder joints are typically used to make the electrical connections between the bus bars and the external connectors.
Unfortunately, it has been found that solder connections between the bus bars and external connectors are undesirable for several reasons. Solder joints tend to be rather thick in cross-sectional profile, which is not desirable when such joints are located in a laminated window between a pair of glass substrates. In the case of a laminated window having two glass substrates, this rather thick profile of a solder joint can lead to undesirable stress between the two glass substrates and the possible cracking of one or both of the glass substrates. In an effort to overcome such problems, some have resorted to a technique of cutting out a notch in the other glass substrate in the area proximate the solder joint so that the significant bump caused by the solder joint does not induce stress on the glass. Unfortunately, this may lead to increased processing costs and capital expenditures, as well as increased manufacturing time. Moreover, soldering requires an electrical power supply, and also the fluxing agent on the connector used in solder sometimes smokes and can cause the solder to splatter and thus discolor and/or contaminate the adjacent surfaces/materials. Still further, solder joints may sometimes lead to higher impedance and hot spots at that location.
In view of the above, it will be appreciated that there exists a need in the art for a heatable window, and/or a method of making the same, where one or more of the aforesaid problems can be addressed.